JP4659345B2 - Coating apparatus and coating method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inkjet-type coating apparatus and a coating method for spraying a solution from a nozzle and coating a substrate.
[0002]
[Prior art]
In general, in a manufacturing process of a liquid crystal display device, a functional thin film such as an alignment film or a resist is formed on the surface of a glass substrate. When a functional thin film is formed on the surface of a substrate, an ink jet type coating apparatus that ejects a solution (a solution for forming a functional thin film) as a material onto the substrate may be used.
[0003]
This coating apparatus has a transfer table for transferring a substrate, and a plurality of heads are arranged in parallel on the upper side of the transfer table so as to intersect with the transfer direction of the substrate. A plurality of nozzles are drilled in the lower surface of each head so as to communicate with the internal liquid chamber. By driving a piezoelectric vibrator provided for each nozzle, the lower side of the head is conveyed. The solution in the liquid chamber can be sprayed toward the substrate.
[0004]
Recently, an ink jet type coating apparatus is sometimes used when supplying liquid crystal between two glass substrates.
[0005]
[Problems to be solved by the invention]
However, since the conventional coating apparatus discharges the solution stored in the liquid chamber from a plurality of nozzles at the same time, even if the same voltage is applied to each piezoelectric vibrator, there may be a difference in the discharge amount between the nozzles. .
[0006]
In addition, when supplying liquid crystal between glass substrates, it is necessary to maintain the supply amount with high accuracy. However, since the conventional supply device cannot detect the integrated supply amount during supply of the liquid crystal, supply The amount could not be controlled accurately.
[0007]
The present invention has been made in view of the above circumstances, and a first object of the present invention is to provide a coating apparatus and a coating method capable of ejecting droplets uniformly from a plurality of nozzles. An object of the present invention is to provide a coating apparatus and a coating method capable of accurately controlling the amount of solution discharged.
[0008]
[Means for Solving the Problems]
In order to solve the above problems and achieve the object, the coating apparatus and the coating method of the present invention are configured as follows.
[0009]
(1) In an inkjet-type coating apparatus that sprays and coats a solution on the surface of a substrate, a transport table that transports the substrate, a head that is provided above the transport table and includes a plurality of nozzles, and that is provided in the head And a piezoelectric vibrator that discharges the solution from the nozzles in the form of droplets when a drive signal is applied, and an imaging unit that can move in the direction in which the plurality of nozzles are juxtaposed. And detecting the droplet information ejected from each nozzle from the captured image, and controlling the drive signal based on the droplet information obtained by the detector comprising control means for adjusting the ejection amount of the solution discharged from the nozzle, the said detection means, said imaging means is successively moved in the arrangement direction of the plurality of nozzles, the individual nozzles And detecting the information issued droplets sequentially.
[0010]
(2) The coating apparatus according to (1), further including a receiving member that receives droplets ejected from the nozzle, wherein the imaging unit images the droplets attached to the receiving member. And
[0011]
(3) Having a head having a plurality of nozzles, and applying a drive signal to the piezoelectric vibrator provided for each nozzle in the head, the solution is ejected from the nozzles in the form of droplets to form a substrate. In the ink jet method, the image pickup means is sequentially moved in the juxtaposition direction of the plurality of nozzles, and the liquid droplets ejected from the individual nozzles are picked up in order by the image pickup means and the image is taken from the picked-up image. A detection process for detecting information on droplets ejected from the nozzles for each nozzle, and a solution to be ejected from each nozzle by controlling the drive signal based on the information on the droplets obtained by the detection process. And a control step of adjusting the discharge amount.
[0012]
(4) A transport table for transporting the substrate, a head having a plurality of nozzles arranged in parallel, a support for supporting the head above the transport table, and a drive signal provided for each nozzle in the head. A piezoelectric vibrator that discharges the solution from the nozzle in the form of droplets when applied, and an inkjet type coating apparatus that sprays and coats the solution onto the surface of the substrate. An image pickup means for picking up an image of a drop that is ejected from each nozzle and falling, and an image processing device for detecting information on each liquid drop based on an image taken by the image pickup means, ,
Control means for adjusting the ejection amount of the solution to be ejected from each nozzle by controlling the drive signal based on the information on each droplet detected by the image processing apparatus, and the imaging means comprises: The plurality of nozzles are sequentially moved in the juxtaposed direction, and the liquid droplets ejected from the individual nozzles are sequentially imaged.
[0013]
(5) An illuminating device is provided opposite to the imaging means, and the illuminating device includes an infrared filter for suppressing the influence of heat caused by light emitted from the illuminating device.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
[0015]
FIG. 1 is a front view of a coating apparatus according to the first embodiment of the present invention, and FIG. 2 is a side view of the coating apparatus according to the embodiment.
[0016]
The coating apparatus shown in FIGS. 1 and 2 has a base 1. Legs 2 are respectively provided at predetermined positions on the lower surface of the base 1, and the base 1 is horizontally supported by these legs 2.
[0017]
At both ends in the width direction of the upper surface of the base 1, attachment plates 3 are provided along the longitudinal direction. A guide member 4 is fixed to each of the mounting plates 3, and a rectangular plate-shaped transport table 5 is disposed on the upper surface thereof.
[0018]
The transport table 5 is slidably supported on the guide member 4 by a slide member 6 having an L-shaped cross section, and is driven along the longitudinal direction of the guide member 4 by a driving device (not shown). ing.
[0019]
A substrate W such as a glass substrate or a semiconductor wafer is detachably held on the upper surface of the transfer table 5. Then, the substrate W held on the transport table 5 is transported along the longitudinal direction of the guide member 4 together with the transport table 5.
[0020]
A gate-shaped support body 7 is provided in the middle of the longitudinal direction of the base 1 so as to straddle the two guide members 4. A mounting member 8 made of a prism is horizontally provided above the support 7, and a plurality of, in this embodiment, eight heads 9 are juxtaposed on one side of the mounting member 8. The lengths formed by these heads 9 are set to be approximately equal to or slightly longer than the width of the substrate W, and the entire substrate W to be transported passes under the head 9.
[0021]
FIG. 3 is a sectional view showing the configuration of the head 9 according to the embodiment, and FIG. 4 is a bottom view showing the configuration of the head 9 according to the embodiment.
[0022]
As shown in FIGS. 3 and 4, each head 9 includes a head body 51. The head main body 51 has an opening 52 that communicates from the upper surface side to the lower surface side, and the lower surface opening is closed by a flexible plate 53. The flexible plate 53 is covered at the lower side by a nozzle plate 54, and a liquid chamber 55 is formed between the flexible plate 53 and the nozzle plate 54. The liquid chamber 55 is filled with a solution supplied from a solution tank (not shown), for example, polyimide forming an alignment film, liquid crystal, or the like.
[0023]
As shown in FIG. 4, a large number of nozzles 56 are formed on the nozzle plate 54 in a line along a direction substantially orthogonal to the longitudinal direction of the head body 51, that is, a direction orthogonal to the transport direction of the substrate W.
[0024]
As shown in FIG. 3, piezoelectric vibrators 58 are fixed on the upper surface of the flexible plate 53 at positions facing the respective nozzles 56. A drive control device 67 (described later) provided outside the head body 51 is connected to these piezoelectric vibrators 58 so that a drive voltage can be applied to each piezoelectric vibrator 58 independently. The piezoelectric vibrator 58 to which the driving voltage is applied partially deforms the flexible plate 53 and causes the corresponding nozzle 56 to discharge an amount of solution corresponding to the driving voltage. Then, the solution discharged from the nozzle 56 becomes droplets and adheres to the surface of the substrate W being transported.
[0025]
As shown in FIGS. 1 and 2, a high-speed camera 61 and an illumination device 62 are disposed above the transfer table 5 so as to face each other. The high-speed camera 61 and the illumination device 62 are fixed by a bracket 63, and the optical axis a is set below the head 9. The high-speed camera 61 uses the light emitted from the illumination device 62 to pick up an image of the droplet L before being ejected from the nozzle 56 and attached to the substrate W. In addition, in order to suppress the influence of the heat by a light ray, you may attach an infrared filter to the illuminating device 62. FIG.
[0026]
The bracket 63 is supported by a ball screw 64 provided horizontally on the upper surface side of the support body 7 so as to be movable along the axis line direction. A motor 65 is provided at one end of the ball screw 64, and by driving the motor 65, the high-speed camera 61 and the illumination device 62 are moved together with the bracket 63 in the direction of the axis of the ball screw 64, that is, in parallel with the head 9. It can be driven back and forth along the installation direction.
[0027]
FIG. 5 is a schematic view showing a configuration of a main part of the coating apparatus according to the embodiment.
[0028]
As shown in FIG. 5, an image processing device 66 is connected to the high speed camera 61. The image processing device 66 calculates the amount of the droplet L based on the size of the droplet L imaged by the high speed camera 61. In the present embodiment, the volume of the droplet L is calculated from the projected area of the droplet L imaged by the high-speed camera 61 on the assumption that the shape of the droplet L is substantially spherical.
[0029]
A drive control device 67 is connected to the image processing device 66. The drive control device 67 is connected to each piezoelectric vibrator 58 in the head 9 and controls the drive voltage of the piezoelectric vibrator 58 based on the volume of the droplet L calculated by the image processing device 66. As a result, the drive voltage of each piezoelectric vibrator 58 is adjusted so that droplets L having a uniform volume are ejected from a plurality of nozzles 56 provided in the head 9. In this embodiment, a pulse signal is used as the driving voltage.
[0030]
Next, the configuration of the drive control device 67 will be briefly described with reference to FIG.
[0031]
FIG. 6 is a schematic diagram showing the configuration of the drive control device 67 according to the embodiment.
[0032]
As shown in FIG. 6, the drive control device 67 includes a CPU 81, a serial-parallel conversion chip 82, and an amplifier 85.
[0033]
The CPU 81 and the serial-parallel conversion chip 82 are connected by a serial signal wiring 83, and the CPU 81 inputs a serial signal for determining ON / OFF of driving of the piezoelectric vibrator 58 to the serial-parallel conversion chip 82 via the serial signal wiring 83. To do.
[0034]
The serial-parallel conversion chip 82 and each amplifier 85 are connected to each other by a parallel signal wiring 84. The serial-parallel conversion chip 82 converts the serial signal input from the CPU 81 into a parallel signal, and inputs each parallel signal to the corresponding amplifier 85.
[0035]
The piezoelectric vibrators 58 are connected to the amplifiers 85, and the piezoelectric vibrators 58 are driven by parallel signals input from the serial-parallel conversion chip 82 via the amplifiers 85.
[0036]
A CPU 81 is connected to each amplifier 85, and the CPU 81 adjusts the gain of each amplifier 85.
[0037]
The CPU 81 is connected to the image processing device 66, and the volume of the droplet L discharged from each nozzle 56 is input.
[0038]
That is, the CPU 81 outputs a serial signal to discharge the droplet L from each nozzle 56, adjusts the gain of the corresponding amplifier 85 based on the volume of the discharged droplet L, and each piezoelectric vibrator 58. The voltage of the drive signal applied to is set. As a result, the volume of the droplet L discharged from each nozzle 56 can be set to a predetermined value.
[0039]
Next, the operation when using the coating apparatus having the above configuration will be described.
[0040]
When the coating apparatus according to the present embodiment is used, the head 9 is first adjusted. Adjustment of the head 9 is an operation of adjusting each head 9 so that the volume (the same in weight) of the droplets L ejected from each nozzle 56 is made uniform by ejecting a solution from the nozzle 56 of each head 9. That is.
[0041]
When adjusting the head 9, first, a predetermined drive voltage is applied to the piezoelectric vibrator 58 designated by the drive control device 67. The piezoelectric vibrator 58 to which the driving voltage is applied partially deforms the flexible plate 53 and causes the solution in the liquid chamber 55 to be ejected as droplets L from the corresponding nozzles 56. At this time, the shutter of the high-speed camera 61 and the discharge of the droplet L are synchronized, and the droplet L discharged from the nozzle 56 is imaged by the high-speed camera 61.
[0042]
The projected area (size) of the droplet L imaged by the high-speed camera 61 is calculated by the image processing device 66, and the volume of the droplet L is estimated based on the projected area. The droplet L discharged from the nozzle 56 adheres to the surface of the receiving member 72 on the transport table 5 that stands by below the head 9.
[0043]
When the volume of the droplet L ejected from the nozzle 56 is calculated, the calculation result is fed back to the drive control device 67, and the piezoelectric so that the volume of the droplet L ejected from the nozzle 56 becomes a predetermined value (target value). The drive voltage of the vibrator 58 is adjusted.
[0044]
When the volume of the droplet L discharged from one nozzle 56 is adjusted, the high-speed camera 61 is moved in the direction in which the nozzles 56 are arranged in parallel, and the drive voltage of each piezoelectric vibrator 58 is adjusted by the same procedure. As a result, the volume of the droplets L discharged from all the nozzles 56 is adjusted to be uniform. This completes the adjustment of the head 9.
[0045]
In the present embodiment, the voltage of the pulse signal applied to the piezoelectric vibrator 58 is adjusted in order to uniformly discharge the droplets L from all the nozzles 56, but the drive voltage is applied to the piezoelectric vibrator 58. The time to perform, that is, the pulse width may be adjusted.
[0046]
When the adjustment of the head 9 is completed, the substrate W is placed on the upper surface of the transfer table 5, and the transfer table 5 is driven at a predetermined speed along the longitudinal direction of the base 1. When the substrate W to be conveyed reaches below the head 9, a driving voltage adjusted by adjusting the head 9 is applied to each piezoelectric vibrator 58, and the solution in the liquid chamber 55 is discharged from each nozzle 56. As a result, a solution composed of droplets L having a uniform volume is sprayed onto the surface of the substrate W.
[0047]
When applying the solution, the high-speed camera 61 is fixed at a predetermined position. The high-speed camera 61 images the droplets L that are sequentially ejected from the target nozzle 56, and outputs a captured image of each droplet L to the image processing device 66.
[0048]
Based on the volume of each droplet L imaged by the high-speed camera 61, the image processing device 66 calculates the integrated volume of the droplet L ejected from the nozzle 56 during application. Thereby, the application amount of the solution applied to the substrate W during application is detected in real time.
[0049]
According to the coating apparatus having the above-described configuration, the solution is sequentially ejected from all the nozzles 56 of all the heads 9 in the preparation stage before the solution coating, and the driving voltage of each piezoelectric vibrator 58 is set based on the volume of the ejected droplet L. It is adjusted.
[0050]
Therefore, when the solution is applied, the droplets L discharged from all the nozzles 56 have a uniform volume, so that the solution can be applied to the surface of the substrate W with a uniform film thickness.
[0051]
Further, the droplet L discharged from the nozzle 56 at the time of applying the solution is continuously imaged by the high speed camera 61.
[0052]
Therefore, since the integrated discharge amount of the solution from the start of solution application can be detected in real time, the supply amount of the solution supplied to the surface of the substrate W can be controlled with high accuracy.
[0053]
Next, a second embodiment of the present invention will be described with reference to FIGS. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0054]
FIG. 7 is a front view showing a configuration of a coating apparatus according to the second embodiment of the present invention, and FIG. 8 is a schematic diagram showing a configuration of a main part of the coating apparatus according to the embodiment.
[0055]
As shown in FIGS. 7 and 8, in the present embodiment, instead of the high-speed camera 61 and the image processing device 66, the receiving member 72 is used as a detecting means for detecting information on the droplet L discharged from the nozzle 56. A droplet confirmation sensor 73 is used.
[0056]
The droplet confirmation sensor 73 is supported by a ball screw 74 provided substantially horizontally on the support 7, and is driven in the direction of its axis by driving a motor 75 provided at one end of the ball screw 74. It has come to be.
[0057]
The receiving member 72 is placed on the upper surface of the transport table 5 and is disposed almost directly below the head 9.
[0058]
In such a coating apparatus, when a driving voltage is applied to the piezoelectric vibrator 58, the solution discharged from each nozzle 56 becomes droplets L and adheres to the surface of the receiving member 72 at a pitch interval of the nozzles 56.
[0059]
Therefore, it is possible to confirm whether or not the droplet L is ejected from each nozzle 56 by scanning the droplet confirmation sensor 73 on the upper side of the receiving member 72 and detecting the droplet L attached to the receiving member 72. it can.
[0060]
The output of the droplet confirmation sensor 73, that is, whether or not the droplet L is discharged is processed by the detection processing device 76 and then input to the drive control device 67. The drive control device 67 confirms the discharge of the droplet L. The drive voltage of the piezoelectric vibrator 58 corresponding to the nozzle 56 not to be adjusted is adjusted. Thereby, it is possible to adjust so that the solution is surely discharged from all the nozzles 56 in the preparation stage before solution application.
[0061]
In the present embodiment, the high-speed camera 61 used in the first embodiment may be used instead of the droplet confirmation sensor 73 described above. In this case, the image processing device 66 used in the first embodiment is connected to the high-speed camera 61, and the volume of the droplet L obtained by the image processing device 66 is fed back to the drive control device 67. In addition to confirming the discharge of the droplet L, it is also possible to discharge the droplet L having a uniform volume from all the nozzles 56.
[0062]
Next, a third embodiment of the present invention will be described with reference to FIGS. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0063]
FIG. 9 is a front view showing a configuration of a coating apparatus according to a third embodiment of the present invention, and FIG. 10 is a schematic diagram showing a configuration of a main part of the coating apparatus according to the embodiment.
[0064]
As shown in FIGS. 9 and 10, in this embodiment, instead of the high-speed camera 61 and the illumination device 62 used in the first embodiment, a detector for detecting the amount of the droplet L is used as a detector. An accuracy balance 71 is used. That is, a high precision balance 71 is provided on the upper surface of the transfer table 5, and the substrate W is placed on the upper surface of the high precision balance 71.
[0065]
When a driving voltage is applied to the piezoelectric vibrator 58, the solution is discharged from the nozzle 56 and becomes a droplet L and adheres to the substrate W on the high precision balance 71. The droplets L attached to the substrate W flow around due to their own weight, and form a liquid film on the surface of the substrate W.
[0066]
When a preset amount of solution (set weight) is applied to the surface of the substrate W, the driving of the piezoelectric vibrator 58 is stopped, and the weight of the solution actually applied to the substrate W by the high-precision balance 71. (Actual application amount) is measured. The set weight is set to be smaller than the weight of the solution finally applied to the substrate W (target application amount). When the actual application amount is measured, the difference from the target application amount is calculated by the application amount processing device 77, and the application of the solution is repeated until the actual application amount reaches the target application amount.
[0067]
In this way, since the integrated weight of the solution discharged from the nozzle 56 can be measured in real time while the solution is applied to the substrate W, the solution applied to the substrate W without complicating the configuration of the apparatus. Can be controlled with high accuracy.
[0068]
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention at the stage of implementation. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
[0069]
【The invention's effect】
According to the coating apparatus and the coating method of the present invention, the discharge amount of the solution discharged from the plurality of nozzles can be made uniform.
[Brief description of the drawings]
FIG. 1 is a front view of a coating apparatus according to a first embodiment of the present invention.
FIG. 2 is a side view of the coating apparatus according to the embodiment.
FIG. 3 is a sectional view showing a configuration of a head according to the embodiment.
4 is a bottom view showing the configuration of the head according to the embodiment. FIG.
FIG. 5 is a schematic view showing a configuration of a main part of the coating apparatus according to the embodiment.
FIG. 6 is a schematic diagram showing a configuration of a drive control device according to the embodiment.
FIG. 7 is a front view showing a configuration of a coating apparatus according to a second embodiment of the present invention.
FIG. 8 is a schematic view showing a configuration of a main part of the coating apparatus according to the embodiment.
FIG. 9 is a front view showing a configuration of a coating apparatus according to a third embodiment of the present invention.
FIG. 10 is a schematic view showing a configuration of a main part of the coating apparatus according to the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 5 ... Transfer table, 9 ... Head, 56 ... Nozzle, 58 ... Piezoelectric vibrator, 61 ... High-speed camera, 66 ... Image processing apparatus, 67 ... Drive control apparatus (control means), 71 ... High precision balance, 72 ... Receipt Member, W ... substrate, L ... droplet.

Claims (5)

In an inkjet type coating apparatus that sprays and coats a solution on the surface of a substrate,
A transfer table for transferring the substrate;
A head provided on the upper side of the transfer table and provided with a plurality of nozzles;
A piezoelectric vibrator provided in the head and ejecting a solution from the nozzle in the form of droplets by application of a drive signal;
The image pickup means that can move in the direction in which the plurality of nozzles are juxtaposed, picks up images of the liquid droplets discharged from the nozzles by the image pickup means, and detects information on the liquid droplets discharged from the nozzles from the picked-up image. Detecting means for
Control means for controlling the drive signal based on the droplet information obtained by the detection means to adjust the discharge amount of the solution discharged from the nozzle;
Equipped with,
The said detection means moves the said imaging means sequentially in the juxtaposition direction of the said several nozzle, and coats the droplet discharged from each nozzle in order, The coating device characterized by the above-mentioned . Has a receiving member for receiving the liquid droplets ejected from the nozzle,
The imaging means, the coating apparatus of claim 1, wherein imaging the droplets adhering to the receiving member. A head having a plurality of nozzles is provided, and a drive signal is applied to the piezoelectric vibrator provided for each nozzle in the head, so that the solution is ejected from the nozzle in the form of droplets and applied to the substrate. In the ink jet method ,
And sequentially moving the imaging means in the arrangement direction of the plurality of nozzles, the information of the droplets discharged from the nozzle than the captured image with the droplets that are ejected from individual nozzles are captured sequentially in the image pickup means A detection step for detecting each nozzle;
A control step of adjusting the amount of solution discharged from each of the nozzles by controlling the drive signal based on droplet information obtained by the detection step;
The coating method characterized by comprising. A transport table for transporting the substrate, a head having a plurality of nozzles arranged in parallel, a support for supporting the head above the transport table, and provided for each nozzle in the head, by applying a drive signal A piezoelectric vibrator that discharges the solution in droplet form from the nozzle, and an inkjet type coating apparatus that sprays and coats the solution onto the surface of the substrate.
An imaging means that is provided on the support so as to be movable along the direction in which the nozzles are juxtaposed, and that images the droplets that are ejected from the nozzles and are falling ,
An image processing device for detecting information of each droplet based on a captured image of the imaging means;
Control means for controlling the drive signal based on the information on each droplet detected by the image processing apparatus to adjust the amount of solution discharged from each nozzle;
Equipped with,
The coating device is characterized in that the imaging means sequentially moves in the direction in which the plurality of nozzles are juxtaposed, and sequentially images the liquid droplets discharged from the individual nozzles . A lighting device is provided opposite to the imaging means,
The illumination apparatus, the coating apparatus of claim 1 or 4 wherein you characterized in that it has an infrared filter for suppressing the influence of heat by the light emitted from the lighting device.

Images